Worm Breeder's Gazette 12(2): 73 (January 1, 1992)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We have mapped the poly A addition site of the unc-54 mRNA by both RNase protection and Reverse Transcription - PCR(1). The 3' end of the message lies 286 base pairs downstream of the translational termination site. Since there are three "A" residues at this point, we can only pinpoint the site of poly A addition to +2 base pairs. There is a GAUAAA sequence located at 9 - 12 base pairs upstream of the poly A addition site(2). Surprisingly an AAUAAA sequence at 165 base pairs downstream of the translational stop site, originally thought to be the signal for poly adenylation(3), is apparently not used.
[See Figure 1]
2. Note that 3' end segments of unc-54 ,used in the modular fusion vectors (Fire, Harrison, & Dixon Gene 93,189), extend 340 base pairs upstream and 450-900 base pairs downstream of the poly A site.
3. Karn, Brenner, & Barnett (PNAS 80, 4253) proposed that the poly A site might lie just downstream of the AAUAAA sequence (shown as *).